In the sewage waste water industry, high pressure hoses are needed to clear and clean the sewage pipes. Sewage trucks are utilized that have large reels having the high pressure main line water hoses. Sewage trucks are also known as combination sewer cleaning trucks, combination trucks, jetters or jetter trucks. The main line can be of varying lengths up to approximately 1000 feet and can have a working pressure of anywhere from 2000-3000 psi. The main line hoses are color-coordinated with the color referring to the water pressure that the truck's pumps can generate.
At the beginning and end of the main line hose there is a leader hose (also referred to as a guide hose or Pilot hose). The leader hoses are more flexible and they have a higher working pressure than the main line hose. The leader hoses are used to lead the main line hose around turns and bends. A high pressure nozzle is connected to the end of the leader hose.
As an industry standard the leader hoses are black. They are extremely difficult to see in dark sewage lines. Workers may use mirrors or flashlights to help them see in the sewage line.
A function of the leader hose is to let the worker know the distance from the nozzle to the end of the main line hose. For example, the workers may see that they have 10 feet left or 15 feet left depending on the length of the leader hose. Leader hoses may be as long as 25 feet. It is important to know where the main line hose is in order to save the main line hose from any unnecessary damage. Unfortunately, as stated above, leader hoses are very hard to see because they are black. Also manhole depths can be high, up to 30 feet.
Europium Phosphorescent Material
Europium phosphorescent powders are a new generation of glow material. The europium phosphorescent powder provides glow much better than the zinc sulfide phosphorescent materials more commonly known. For example, green and aqua glow europium phosphorescent powders will remain clearly visible for as long a 30 hours sufficient light exposure. The length of time a glow powder will glow is defined as the time it takes for the afterglow brightness to diminish to 0.32 mod (0.32 mod is 100 times the human visible perception limit). Even at this level, the glow is clearly visible in darkness. Europium phosphorescent powder is available from United Nuclear Scientific with offices in Laingsburg, Mich.